China Says Yutu Lunar Rover Possibly Damaged by Rocks, Sample Return Mission Slips to 2020

As America celebrates the 45th anniversary of the Apollo 11 landing of astronauts on the Moon, China is providing an update on its robotic Yutu rover that arrived on the lunar surface last December.  Yutu suffered a malfunction that prevents it from moving across the lunar surface, but it is still transmitting back to Earth. Its designers now speculate that it was damaged by collisions with rocks.  Meanwhile, the Chang’e-5 robotic lunar sample return mission apparently has been delayed until 2020.

The 140-kilogram, six-wheeled Yutu rover is part of the Chang’e-3 mission, which landed on December 14, 2013.  Chang’e-3 is a stationary lander that delivered Yutu to the lunar surface.  The two are named after Chang’e, China’s mythological goddess of the Moon, and her pet rabbit, Yutu (Jade Rabbit).

Yutu rolled off Chang’e-3 on December 15, 2013 and began its trek across the lunar surface.  The Moon has a 28-day cycle during which 14 days are in sunlight (“day”) and 14 days are darkness (“night”).  Yutu’s primary power source is its solar panels and therefore was designed to operate during the “day” and hibernate at “night,” refolding its instruments and other key equipment into an internal compartment where a small radioisotope heating unit provides enough warmth to protect them from the bitter cold (minus 180 degrees Celsius) of the lunar night.  The plan was for Yutu to survive three day-night cycles, roving across the lunar surface during the day to collect geological and resource information from a variety of sites.

The process worked the first time, but then “a mechanical malfunction” occurred and the rover could no longer move.   Official Chinese sources provided little information about the cause, but acknowledged in March that the equipment failed to return to its folded, protected state as the second night period commenced.

China’s official news agency, Xinhua, reports today (July 21), however, that Yutu’s deputy chief designer, Zhang Yuhua, said that rover may have been damaged by colliding with rocks.  She said the terrain at the landing site was quite different than expected — “almost like a gravel field.”

Yutu remains motionless just 20 meters from its landing point.  It is still transmitting back to Earth, however, after seven lunar cycles, four more than planned,  On that level, at least, the mission is a success even though it cannot rove.  Previously, Chinese sources said that roving was a critical aspect of the scientific mission because Yutu was intended to investigate different sites on the Moon.  Today, however, Yutu’s chief designer, Wu Weiren, is quoted by Xinhua as saying that “fortunately, the rover has completed its designated scientific and engineering tasks.”

Chang’e-3 is part of China’s second phase of robotic lunar exploration.  The first phase involved the launch of two lunar orbiters Chang’e-1 and Chang’e-2,  in 2007 and 2010, respectively.  Phase 2 is Chang’e-3 and its twin, Chang’e-4, both lander/rovers.  At last report, Chang’e-4 was intended to be launched in 2015, although that schedule could change if the design needs modification. 

The third phase is a robotic lunar sample return mission with Chang’e-5.  Chinese officials said as recently as March that Chang’e-5 would be launched in 2017, but today’s Xinhua states that it will launch “around 2020.”

Chang’e-5 will use China’s new Long March 5 rocket, a “heavy lift” launch vehicle still in development that will be roughly equivalent to the U.S. Delta IV Heavy.   China is building a new launch site for the Long March 5, Wenchang Satellite Launch Center, on Hainan Island.   Whether the delay in launching Chang’e-5 is due to the spacecraft, launch vehicle or launch site is unclear.  The U.S. Department of Defense’s most recent annual report on China’s military and security developments says that the first Long March 5 launch has been delayed to 2015 (from 2014) because of manufacturing difficulties.